According to the PRM (Vol3P2), the PCH FDI receiver ISR read for bit lock
should be retried at least once. This patch retries the read 5 times
with a small delay in between reads. I've had reports of display corruption
on resume with "FDI train 1 fail!", so I'm hoping that adding this retry
will mitigate the issue.
Signed-off-by: Sean Paul <seanpaul at chromium.org>
---
drivers/gpu/drm/i915/intel_display.c | 42 ++++++++++++++++++++-------------
1 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index de1ba19..615b397 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2537,7 +2537,7 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc)
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
int pipe = intel_crtc->pipe;
- u32 reg, temp, i;
+ u32 reg, temp, i, retry;
/* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
for train result */
@@ -2589,15 +2589,19 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc)
POSTING_READ(reg);
udelay(500);
- reg = FDI_RX_IIR(pipe);
- temp = I915_READ(reg);
- DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
-
- if (temp & FDI_RX_BIT_LOCK) {
- I915_WRITE(reg, temp | FDI_RX_BIT_LOCK);
- DRM_DEBUG_KMS("FDI train 1 done.\n");
- break;
+ for (retry = 0; retry < 5; retry++) {
+ reg = FDI_RX_IIR(pipe);
+ temp = I915_READ(reg);
+ DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
+ if (temp & FDI_RX_BIT_LOCK) {
+ I915_WRITE(reg, temp | FDI_RX_BIT_LOCK);
+ DRM_DEBUG_KMS("FDI train 1 done.\n");
+ break;
+ }
+ udelay(50);
}
+ if (retry < 5)
+ break;
}
if (i == 4)
DRM_ERROR("FDI train 1 fail!\n");
@@ -2638,15 +2642,19 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc)
POSTING_READ(reg);
udelay(500);
- reg = FDI_RX_IIR(pipe);
- temp = I915_READ(reg);
- DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
-
- if (temp & FDI_RX_SYMBOL_LOCK) {
- I915_WRITE(reg, temp | FDI_RX_SYMBOL_LOCK);
- DRM_DEBUG_KMS("FDI train 2 done.\n");
- break;
+ for (retry = 0; retry < 5; retry++) {
+ reg = FDI_RX_IIR(pipe);
+ temp = I915_READ(reg);
+ DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
+ if (temp & FDI_RX_SYMBOL_LOCK) {
+ I915_WRITE(reg, temp | FDI_RX_SYMBOL_LOCK);
+ DRM_DEBUG_KMS("FDI train 2 done.\n");
+ break;
+ }
+ udelay(50);
}
+ if (retry < 5)
+ break;
}
if (i == 4)
DRM_ERROR("FDI train 2 fail!\n");
--
1.7.7.3
